[mgarblik]

To be clear, is the "421 hole" the small hole in the center area of the deck? The gasket has that unused hole. Neither the heads or block have that hole drilled.

[Tom Vaught]

Originally Posted by mgarblik

He wants as little outside plumbing and extra crap under the hood as possible.

The only way to go with that type of racing. 'Also, as far as safety equipment goes, a "fire suppression" system has to have a minimum of one nozzle under the hood and one nozzle inside the drivers compartment. TV

4. There shall be a minimum of two nozzle locations–one in the driver’s compartment and one in either the engine area or the fuel cell area.

The nozzles shall be suitable for the type of extinguishing agent used.

5. The firing safety pin(s) shall be removed from all on-board fire systems prior to going on track. It is recommended that a warning tag be attached to the safety pin to remind the driver to remove the safety pin before entering the racing surface.

6. All fire systems shall be serviced according to manufacturer’s specifications.'

So TRY to make the underhood and inside of vehicle as "Clean" as you can with-in the rules.

Tom V.

[PAUL K]

Originally Posted by mgarblik

To be clear, is the "421 hole" the small hole in the center area of the deck? The gasket has that unused hole. Neither the heads or block have that hole drilled.

Yes, that is the one I am referring to.

[Dragncar]

Originally Posted by mgarblik

Yes, that would be the easy way to do it. Glutton for punishment I guess. Doing this on my own time. Nobody is paying for my extra effort on this one. Agree the wide sleeve flange would hold a magnetic drill. I would like to use a mill because I would like to put a bunch of the holes in with an end mill. I don't think a magnetic drill will have the spindle speed to use anything other than a twist drill. On a drag race engine I would just put all small holes in the block, like 5/16" and 1/4". But for road racing I want maximum water flow to the heads where the heat will be generated. A dry deck is not an option for this one. He wants as little outside plumbing and extra crap under the hood as possible.

You are right, mag drills are even slower than your average drill press or hand drill.
Anyone remember that movie Panic Room ? Jodie Foster and Forest Whitaker were in it.
Well Forest (bad guy) has a duffel bag and pulls out a Milwaukee Mag Drill.
Yeah right, they are like lead. Not happening.
Sorry to get OT guys.

OK, at this point, rods pistons in, deck mirror finish, High Ports, filled block, 1016s.
Is there any point on drilling this hole ? Is is a Cometic only deal ?
Reason I am asking is engine s 11.5-1 CR and pushing it on pump gas and cooling will be a issue.

[mgarblik]

Originally Posted by PAUL K

Yes, that is the one I am referring to.

I will have to see if the KRE High Ports are open to water in that spot. If they are, it seems like a good idea to drill the block and head? I assume that puts extra water right where the 2 exhaust valves are side by side?

[misterp266]

Here’s a link to an old discussion on the 421 hole.

http://forums.maxperformanceinc.com/...d.php?t=583733

[Skip Fix]

I don't remember if my E heads did or not form them but I drilled the hole in the block . and made sure the E heads had a clean hole also.

[PAUL K]

Originally Posted by mgarblik

I will have to see if the KRE High Ports are open to water in that spot. If they are, it seems like a good idea to drill the block and head? I assume that puts extra water right where the 2 exhaust valves are side by side?

I think it's a good idea. We normally close (or don't add) some of the water holes around the front two cylinders. We try to get as much coolant as possible flowing around that area between the center cylinders. It sèems to help on our street/strip and drag race engines.

[slowbird]

The HP heads can be drilled for the 421 cooling hole. Mine are and i never had a head gasket issue (16.5:1 compression and 1050hp)

[mgarblik]

Thanks for all the replies. I have some good ideas from the old "421 hole" thread and various input here. The progressively larger holes as you move back in the block makes sense and the factory blocks have that idea going on. You certainly don't want the loop shortchanged with the water entering and looping back to the thermostat housing without traveling the length of the block removing heat. Smaller holes in the front would help more of the incoming water reaching the back of the block. That all makes sense. Aluminum block and heads helps, lots of water flow and big radiator as well. 1/2 hour to 45 minutes of near full throttle will produce allot of heat. I will post up some pics of what I end up with next week. I am not going to modify the Cometic gasket, so my holes will stay within the confines of their hole sizes. But they are plenty big enough.

[lust4speed]

Originally Posted by PAUL K

...I've never done one on an aluminum block, but the iron blocks need it drilled on a slight angle leading the drill bit end towards the water jacket.

Aluminum blocks also need the angle drilling to prevent infringing on the thick cylinder walls. The hole location matching the gasket is really forgiving compared to missing the wall. It took us to the third hole before figuring out the necessary angle to keep clear of the wall.

[Skip Fix]

I do think my iron IA the cylinder wall were pretty close to the 421 hole vs a factory block

[mgarblik]

I have all 28 water holes milled into the IA 2A block. I am happy with the results. Did take considerable time. Have about 4 hours in the operation once i rounded up all the necessary tooling, fixtures and got the mill set-up properly. I did not drill any of them. I plunge cut them all with end mills. That way I could locate them right where I wanted them to go. Used a combination of 1/4, 5/16" and 3/8" end mills. The deck on these blocks is very thick, nearly 3/4" inch in some areas. Some of the 3/8" holes just graze the OD of the aluminum which the sleeves are installed into. I was able to stay off all the sleeve flanges, but some are very close. I used ideas posted by some of you and Steve Barcak. I did not include the "421 hole" as discussed here. It looked like only a tiny hole would be possible and just decided not to add it. Here are a couple pics,

[PAUL K]

Looks good! Thanks for sharing

[Skip Fix]

Looks good.

[mgarblik]

Here are the final call outs for the cooling hole sizes. These require no modifications to the Cometic gasket referenced above. Some of the holes are just "cheated" slightly to stay off the sleeve flanges. Also, smaller holes are used around cylinder 1,2 to try and influence more water to the rear of the heads. We will see how it works.

[PAUL K]

Looks good!